Tuesday, October 28, 2014

Floating Ghost Bubbles!

Can you tell we had a lot of dry ice to work with?   We did not mind though as dry ice experiments are so much fun.  We started by taking a closer look at the dry ice.  We poured a few pounds of dry ice pieces into a large plastic container with a towel below it.   After a while we noticed a mist was forming at the bottom of the container and wondered if we could learn more about it.  So what would happen if we blew bubbles over it?

Well those might look like bubbles that are just floating in the air but they are actually floating on an invisible sea of carbon dioxide or the gas from the dry ice.  They hung in the air and gently bobbed around the container keeping at about the same level.

One bubble touched a piece of dry ice and slowly froze.   You could see the outer surface freezing over and then the bubble started to fold in on itself as the air inside got colder.   The girls thought this was fascinating that we could make our bubble into a football!

We blew some more bubbles and even managed to get a big bubble to float around!

By now the girls really wanted to pop the bubbles.  Just to be safe we gave them spoons to pop the bubbles with as we did not want little hands reaching into the cold.   It was not long before they were putting the spoons on the ice.  Do you know what happens when you put a warm spoon on a piece of dry ice?   Try it and leave us a comment telling us what happened.   We probably found this result more fun than the floating bubbles!

After all our experiment fun there is only one way that we can end the day with all this dry ice - taking our container outside and pouring water over all the dry ice!

As you can see in this picture the gas is sitting inside the container and then spilling over the edge.   The carbon dioxide (dry ice gas) is heavier than air so it sinks down to the bottom.  This is why the bubbles will float over the dry ice.  The gas forms a heavier layer of air that the bubbles (filled with room air) will float on top.

  • Dry ice
  • Bubble solution and wand
  • Plastic container

  1. Break up dry ice using a mallet and pour a few pounds of pieces into a large plastic container.
  2. Wait a few minutes and then blow bubbles over the top and watch the bubbles float on an invisible sea across the container.
  3. At the end pour some water on the dry ice and see the large amounts of carbon dioxide form.


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